Thermally conductive elastomers are elastomeric materials which contain a thermally conductive filler. They are primarily used in electronics applications in instances where good thermal conduction and electrical insulation are needed in the same material. For example, a thermally conductive elastomer may be used as an interface between a semiconductor electronic component and a metal heat sink.
Many electronics designs and applications are linked by the ability to dissipate ohmic heat generated during the operation of the electronics. Many electronic components, especially semiconductor components, are prone to breakdown at high temperatures. Thus, the ability to dissipate heat is a limiting factor on the performance of the component.
High thermal conductivity metal heat sinks, because of their high electrical conductivity, cannot be directly contacted with electronic components. Therefore, thermally conductive elastomer material is used as a thermally conductive, electrically insulating interface between the electronic component and the metal heat sink. The thermal conductivity of thermally conductive elastomer is generally much less than that of the metal heat sink. Thus, the thermal conductivity of the thermally conductive elastomer limits the overall ability to dissipate ohmic heat.
Typical thermally conductive elastomers contain a ceramic filler such as boron nitride or alumina in an elastomer matrix. The alumina is generally in the form of irregularly shaped .alpha.-alumina particles. The elastomers used are usually urethane or silicone based. While these materials are adequate in many instances, there is a constant demand for thermally conductive elastomers with improved thermal conductivity and electrical insulating properties.